1. Field of the Invention
The present invention relates to the methods of and apparatus for preparing and inserting flexible intraocular lenses used in the field of ophthalmology wherein flexible intraocular lenses made of silicone and/or other deformable materials are inserted into the eye to replace natural lenses during cataract surgery, and to a configuration for flexible intraocular lenses. More particularly, the invention relates to methods, apparatus and lenses used in the field of ophthalmology wherein flexible intraocular lenses made of silicone and/or other deformable materials are inserted into the eye to replace the natural lens during cataract surgery.
2. Background Art
In cataract surgery, a cataractous human lens is removed through a 3 mm or larger incision by phacoemulsification. A prosthetic intraocular lens is then substituted for the human lens. The intraocular lens obviates the patient's need for a high dioptric power spectacle correction after surgery, which would otherwise be necessary.
Intraocular lenses may be made of flexible materials such as silicone. Although lenses made of these materials have dimensions in their uncompressed state which are larger than 3 mm, such lenses may be folded in various configurations and inserted through 3 mm or slightly larger incisions. When using flexible intraocular lenses, surgical incisions necessary for performing cataract surgery need not be enlarged following phacoemulsification. Accordingly, surgically induced trauma is minimized, healing and convalescence time are reduced, visual recovery for the patient is expedited, and the chance of intraoperative and postoperative complications relative to the wound are minimized.
Flexible intraocular lenses have two essential components, the first being a central optic component which is round or oval in shape and approximately between five and seven millimeters in diameter. The optic component replaces the dioptric power of the cataractous lens after cataract extraction. The second component(s) are attached to the optic component, and extend peripherally therefrom. Known as haptics, these provide internal fixation and centration of the intraocular lens after its insertion into the eye. The haptics may be flexible plates extending outward from the optic component as a unitary extension thereof. Alternatively, the haptics may be joined to the optic component and configured as open loops, termed "C" or "J" loops. The function of both haptic structures is similar.
The patent literature includes a number of patents directed to methods, apparatus and lenses utilized in phacoemulsification cataract surgery. Of particular interest in U.S. Pat. No. 4,681,102 to Bartell incorporated herein by reference which is directed to apparatus for and methods of inserting flexible intraocular lenses through 3 mm incisions. While Bartell suggests an approach to the general technique, there is a need for simpler alternative approaches which are easy to perform and employ ordinary ophthalmological surgical instruments. In addition, there is a need for approaches which allow insertion of flexible intraocular lenses through smaller incisions less than 3 mm in length, and for methods and apparatus applicable to further reducing the effective size of the intraocular lens prior to its insertion. This need is made evident by a host of U.S. Pat. Nos. such as 5,178,622; 5,171,319; 5,171,241; 5,176,686; 4,950,289; 4,894,062; 4,836,202; 4,834,751; 4,664,667; 4,715,373; 4,763,650; 4,785,810; 4,834,750; 4,844,065; and 4,862,885, each of which is incorporated herein by reference.